Preferential tumor localization in relation to 18F-FDOPA uptake for lower-grade gliomas.

Hiroyuki Tatekawa,Phioanh L Nghiemphu,Timothy F Cloughesy,Albert Lai,Hiroyuki Uetani,Noriko Salamon,Shadfar Bahri,Linda M Liau,Akifumi Hagiwara,Catalina Raymond,Whitney B Pope,Talia C Oughourlian,Issei Ueda,Jingwen Yao,Benjamin M Ellingson

doi:10.1007/s11060-021-03730-w

Abstract

Although tumor localization and 3,4-dihydroxy-6-18F-fluoro-L-phenylalanine (FDOPA) uptake may have an association, preferential tumor localization in relation to FDOPA uptake is yet to be investigated in lower-grade gliomas (LGGs). This study aimed to identify differences in the frequency of tumor localization between FDOPA hypometabolic and hypermetabolic LGGs using a probabilistic radiographic atlas. Fifty-one patients with newly diagnosed LGG (WHO grade II, 29; III, 22; isocitrate dehydrogenase wild-type, 21; mutant 1p19q non-codeleted,16; mutant codeleted, 14) who underwent FDOPA positron emission tomography (PET) were retrospectively selected. Semiautomated tumor segmentation on FLAIR was performed. Patients with LGGs were separated into two groups (FDOPA hypometabolic and hypermetabolic LGGs) according to the normalized maximum standardized uptake value of FDOPA PET (a threshold of the uptake in the striatum) within the segmented regions. Spatial normalization procedures to build a 3D MRI-based atlas using each segmented region were validated by an analysis of differential involvement statistical mapping. Superimposition of regions of interest showed a high number of hypometabolic LGGs localized in the frontal lobe, while a high number of hypermetabolic LGGs was localized in the insula, putamen, and temporal lobe. The statistical mapping revealed that hypometabolic LGGs occurred more frequently in the superior frontal gyrus (close to the supplementary motor area), while hypermetabolic LGGs occurred more frequently in the insula. Radiographic atlases revealed preferential frontal lobe localization for FDOPA hypometabolic LGGs, which may be associated with relatively early detection.

Highlights

Superimposition of regions of interest showed a high number of hypometabolic lowergrade gliomas (LGGs) localized in the frontal lobe, while a high number of hypermetabolic LGGs was localized in the insula, putamen, and temporal lobe
The statistical mapping revealed that hypometabolic LGGs occurred more frequently in the superior frontal gyrus, while hypermetabolic LGGs occurred more frequently in the insula
Radiographic atlases revealed preferential frontal lobe localization for FDOPA hypometabolic LGGs, which may be associated with relatively early detection

Summary

Introduction

Tumor localization is a key factor in the care of patients with lower-grade glioma (LGG) as it correlates with their demographic characteristics, molecular status, clinical presentation, surgical management, and survival time. LGGs were more likely to invade the insula in elderly patients than in young patients, where they tended to localize in the temporal lobe [1]. Only 20% of isocitrate dehydrogenase (IDH) wild-type gliomas were localized in the frontal lobe, while IDH mutant LGGs, especially with 1p19q co-deletion, were more likely to occur in the frontal lobe [2,3,4]. For the evaluation of tumor distribution, several studies employed a probabilistic magnetic resonance imaging (MRI)-based brain atlas to specify the probability of anatomical tumor localization associated with the patients’ characteristics (age and sex) [7], clinical presentation (symptoms and Karnofsky performance) [8], and molecular status (IDH, epidermal growth factor receptor, O6-methylguanine methyltransferase, and phosphatase and tensin homolog) [9, 10]

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Conclusion